R2 C-terminal peptide inhibition of mammalian and yeast ribonucleotide reductase

• Published in: Journal of medicinal chemistry Vol. 36; no. 24; pp. 3859 - 3862
• Main Authors: Fisher, Alison, Yang, Fu De, Rubin, Harvey, Cooperman, Barry S
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 26-11-1993
• Subjects: Acetylation; Amino Acid Sequence; Animals; Antibacterial agents; Antibiotics. Antiinfectious agents. Antiparasitic agents; Biological and medical sciences; Cattle; Medical sciences; Mice; Molecular Sequence Data; Oligopeptides - chemical synthesis; Oligopeptides - pharmacology; Pharmacology. Drug treatments; Ribonucleotide Reductases - antagonists & inhibitors; Saccharomyces cerevisiae; Saccharomyces cerevisiae - enzymology; Species Specificity; Structure-Activity Relationship; Vertebrata; Yeast; Mammalia; C terminal peptide; Structure activity relation; Ribonucleoside-triphosphate reductase; Enzyme; Analog; Enzyme inhibitor; Oxidoreductases; Ribonucleoside-diphosphate reductase; Antimicrobial agent
• ISSN: 0022-2623; 1520-4804
• DOI: 10.1021/jm00076a015

Eucaryotic ribonucleotide reductases (RR) catalyze the reduction of ribonucleoside diphosphates to 2'-deoxyribonucleoside diphosphates. Each has an R1(2)R2(2) quaternary structure with each subunit playing a critical role in catalysis. Separation of the subunits results in loss of activity. Previous studies have demonstrated that peptides corresponding to the C-terminus of R2 disrupt subunit association by competion with R2 and have potential usefulness as therapeutics. Extensive structure-function studies have been carried out on peptide inhibition of herpes simplex RR in an effort to develop antiviral agents based on the observation that the herpes simplex R2 C-terminus, YAGAVVNDL, is quite different from the corresponding mammalian sequence. In this work we report a detailed structure-function analysis of peptide inhibition of mammalian and, to a more limited extent, Saccharomyces cerevisiae RRs. Our results for mammalian RR support the following conclusions with regard to the effect of substitution on inhibitory potency: (a) the N-acetylated R2 C-terminal heptapeptide N-AcPhe384Thr385Leu386Asp387Ala388Asp389Phe390 (N-AcF7TLDADF1) is the minimal core peptide length required; deletion of the N-terminus or of middle positions (resulting in penta- and hexapeptides) results in large losses in inhibitory potency; (b) a free carboxylate is required on the C-terminal Phe; (c) Phe is strongly preferred to Leu in positions 1 and 7 and a bulky aliphatic group is preferred in position 5; (d) neither negative charge in positions 2 or 4 nor a polar side chain in position 6 are required for peptide binding, contrary to what evolutionary patterns in the R2 C-terminus of RR would suggest. S. cerevisiae RR displays a similar length dependence on the corresponding N-acetylated R2 C-terminal heptapeptide, N-AcFTFNEDF. This peptide has a 4-fold higher inhibitory potency toward S. cerevisiae RR than toward mammalian RR. Such selectivity raises the possibility that peptide analogs related to R2 C-termini can be developed as therapeutic agents even against organisms having R2 C-terminal sequences similar to that of mammalian RR.